1. Field of the Invention
The present invention relates to a backlight unit capable of improving the bright light generation and a liquid crystal display device having the same.
2. Discussion of the Related Art
Based on rapidly developing semiconductor technologies, demands on compact and light flat display devices with high performance are drastically increasing.
A liquid crystal display device (LCD) receiving public attention recently among the flat display devices has various advantages such as compactness, lightness, and low power consumption. That is, the LCD gradually attracts public interest as a substitute means capable of overcoming limitations of a cathode ray tube (CRT) and thus becomes widely used in almost all information processing devices that require a display unit.
The LCD injects a liquid crystal material between a color filter substrate having a common electrode and a color filter and an array substrate having a thin film transistor and a pixel electrode, and then applies respectively different electric potentials on the pixel electrode and the common electrode. Therefore, the LCD changes arrangements of liquid crystal molecules, thereby adjusting transmittance of light in order to display an image.
Since a liquid crystal display panel including the color filter substrate, the array substrate, and the liquid crystal is a light receiving device that does not emit light by itself, it includes a backlight unit at its bottom in order to provide light.
The backlight unit includes a light source, a light source housing surrounding the light source to prevent light loss, a light guide plate converting a light emitted from the light source into a plane light, a reflective sheet disposed on the rear of the light guide plate, and optical sheets disposed on the light guide plate.
The light source extensively uses a cold cathode fluorescent lamp (CCFL) having relatively less emitted heat and a long life span and also generating a white light close to a natural light. Additionally, a medium/small LCD commonly uses a light emitting diode (LED) having compactness, excellent color reproduction, and also less power consumption.
However, when the backlight unit of the above structure is bent due to pressure from the external, a gap between a light guide plate and a reflective sheet is formed and a portion of light is incident to the gap. Thus, the bright line occurs around the gap. That is, if components of the backlight unit move freely or are modified by the external conditions in a related art LCD, light leaks from an edge area between the light guide plate and the reflective sheet and then directly enters the liquid crystal display panel. Therefore, the edge area is brighter than other areas in an effective screen display unit.